ALSA: ASoC: WM8903 I2C cleanups

Fix a few issues identified by Jean Delvare:

 - Add missing newline to error display.
 - Return an error when we fail to locate the I2C adaptor.
 - Remove the static wm8903_i2c_device Jean suggested, it's redundant.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>